Well-boring tool



March 17,1925.

R. FT. JENKINS ETAL fwELL BORING TOOL Fila Noir. 14', '1922 u v leach tool being leachl end of the shorter axis and obelow the lower face or s from falling out. The bit-body includes a the bore rod,

into a coupling 5. c Y

At'each side and at each end that fis on the screwed threaded nipple 4 formedto screw body.

1t will be observed that the edges of one pairl of tools 6, 6 are arranged in a plane slightly above the cutting edges of the drill y 2, andl that the edges of the other pair of i movable but not rotatable in tools 7, 7 .are disposed in a plane slightly higher still. Thus the drill 2 bores a hole 8 (Fig. 1) the tools 6, 6 cut an annulus 9 and the tools 7, 7 an annulus 10. -The hole is thus progressively enlarged to the diameter required to be bored by the bit.

The shank of each chisel-edged tool .is

longitudinally slotted as at 11,'and the outer face is recessed as at 12 about said slot to accommodate theV head of a set-screw 13 which passes through the slot 11 and screws into any one of a series of threaded holes 14 in the body. Thus longitudinal adjustment of the tools to compensate vfor wear, is permitted. 1

The sleeve .5 into which is screwed the nipple 4 of the bit-body is screwed on to a nipple 15 constituting a reduced part of the reamer body configuration shown in Fig. 4, and formed to freely pass through the casing to be used.

On diametrically opposite sides the -body is slotted as at 17 and in each Slot isan' arm 18 pivotally hung on a bolt 19 and formed at its otherlend into a. head 2O carrying chisel-edge tools 21 fitted in dovetail radial slots in the head, and 'secured therein by dovetailed plates .21l and set-screws 212. Secured by means of pins or setscrews 221 to the inner face' of each arm is a wedge .block 22which projects through a slot 23 into the rectangular bore of the-body. In said bore is a rectangular plunger 24 which is formed at-its inner end to provide bev-` elled surfaces' 25 'which co-operate with the wedge blocks 22 as hereinafter explaiped.

The plunger is connected at" its upper end to the tubular bore rod 26, and is axially the reamerbody, the axial movement being limited. On opposite sides the plunger is recessed as at 27 and a pair of square keys 28 fitted through the body partly take in said rc1 cesses.' Thus the limit of axial movement of the plunger is determined by the length of the recesses less the width of; the keys, and the length of such movement is so fixed that when the reamer-body is suspended on lthe upper oulder of the 'When in this position 16 which is of the sectional medew it moves downwardly on the plunger 24 until the keys 28 contact with shoulders of the recessesv 27. When in this position the bevelled surfaces 25 ofthe plunger are in their highest position relatively tothe wedge blocks 22 and the arms 16 are permitted to swing inwardly 'so that theyareflush with the sides of the body Vas shown in Fig. 2. When however thereamer-body is supported by the bit (as when the tool asa whole is in operation) the weight of or on `the bore- Arod 26 forces thev plunger 24l downwardly in the reamer-body and the bevelled surfaces 25 on the'plunger contact with the wedge blocks 22 and force the arms outwardly -to operative position as shown in Fig.- 1.

operateto cut an -annulus 29 aboutthe annulus 10 previously cut by the tools 7, 7. The major diameter of the annulus29 is not less than the external diameter of the casing to be used; and as the contracted reamer head is to be capable of passing upwardly through the casing, it is obvious that the radial movement ofthe swinging end of each arm must be'not the cutting tools 21 less than the thickness of said casing. -As an additional means e of limiting the .axial `movement of the arms 18 projections 181 are formed on the upper side of the head of arms 18 and recesses 182 are provided in the underside of the reamer body 16, so that the faces of projections 18L contact with the sides of the'recessesl2 whenthe arms 18 are expressed to the 'desired amount.

To avoid strainon'the pivotal bolts n19, the slots in which the arms 18 are housed,

terminate in shoulders 30 against vwhich the.

top ends of the arms bear when they the arms are in operative position-see Fig. 1. Similarly ythe cutting tools 6 and 7 of the bit bear against shoulders 32 formed in the bitbo'dy.

For the application of water during'the boring` operation, the plunger 24, nipplesV 15 and 4 and bit-body 1 are all axially bored,

the bore in the bit-body bommunicating with four divergent discharge holes 31.

What we claim and desire to secure by Letters Patent is 1. In a well-boring tool, the combination with a bit capable of passing through the casing to be used, of ya following 'underreamer comprising a body also capable of passing through said casing and having a rectangular axial bore, a plunger slidably fitting in said bore and formed for attach-v l ment to the bore rod said-plunger having oppositely disposed bevelled surfaces', stops limiting `the travel of said plunger relatively to the body, a pair of swinging arms disposed within longitudinal rooves on the surface of the body and-pivoted attheir upper ends to said body, wedge blocks projecting inwardly from said arms through apertures in the wall of the body and co4y moved inwardly in the body but permitting their retraction when said plunger is movedv outwardly, and cutting tools on the swinging ends of said arms, the whole so constructed that when said arms are retracted the under-reamer will pass through said casing, and when radially expressed the cutting tools thereon o crate to enlarge the hole previously formedp by the bit, to a diameter not less than the external diameter of the casing.

2. In a well-boring tool including a bit capable of passing through the casing to be used, and a following under-reamer, an under-reamer comprising al body also capable of passing through said casing and formed 'at one end for attachment to said bit, a rectangular plunger slidably fitting in a rectangular bore in said body, said plun er being formed at its outer end for attac of swinging arms in longitudinal grooves entvto the bore-rod, and on its inner e'nd with opposed bevelled surfaces, a pair on the sides of the body, said arms being pivoted to the body at their upper ends and normally lying within said grooves, a head on `the swinging end of-each arm, cutters mounted in said head, wedge blocks on said arms projecting inwardly through apertures in the body to co-operate with the bevelled surfaces on the plunger, a recess on each of two opposite. sides of the plunger, and transverse keys in the body engaging said recesses, and limiting the outward movement of the plunger relatively to the body, the whole so constructed and arranged that inward 'movement of the plunger in the body radially expresses the cutter carrying arms, and outward movement permits same to swing inwardly so that the reamer as a whole may be withdrawn through the casing of the bore-hole, projections formed on the heads of the swinging arms to engage recesses in the said body for the purpose of 1imiting the outward movement of the swinging arms. t v 1 Signed at Sydney, N. S. W., this twentyfifth day of September, A. D. 1922;

RICHARD' roRD JENKms. l DAVID WALTER PRICE. 

